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Remote displacements problem

• Fabrizio Fronda
Subscriber

Hi, I have to conduct a static analysis of a skid landing gear with a mass attached to it. I am having some problems with the remote displacements for the two skids. I was told to apply an X=Y=Z=0 desplacements and RotX=RotY=0 but RotZ=Free for one skid and X=Z=RotX=RotY=RotZ=Free but Y=0 for the other skid in order to prevent rigid body motion. Unfortunetely the equivalent Stress seems a little weird to me, I expected to be something more "symmetric" but, as you can see in Pic A, it seems that just two tubulars on the left withstand to the load, however the values are pretty "normal":

I have also tried a new configurations for the remote displacements. In Pic B the left skid has X=Free,Y=0,Z=Free,RotX=RotY=0 and RotZ=Free; the right skid has the exact configuration of the left one; now, the values of the stress are unusually high but his distribution is more symmetric:

The problem is that I can't reach the symmetric stress distribution and normal values at the same time. Thanks to everyone who can help me.

• Aniket
Ansys Employee

Are the materials the same for the structure? can you show the boundary conditions as applied?

-Aniket

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• Fabrizio Fronda
Subscriber

Hi Aniket, yes, the material is the same for all the skids and tubulars, it's Aluminum Alloy 7075. Just some info: in order to obtain a proper mesh, I had split the landing gear in 8 parts (2 skids and 6 tubulars) and after that I connected all the bodies with the default connections. By the way here are the remote displacements: in Pic A and B you can see the RDs for the first configuration (the asymmetrical one with low stress values); in Pic C and D you can see the RDs for the second configuration(the symmertical one with high stress values).

I have also created a remote displacement for the upper tubulars and promoted it in order to attach the remote mass :

And thank you for the quick answer.